Process for manufacturing individual pipe sections of a pipe system, and pipe system manufactured in said manner

ABSTRACT

The invention concerns a method for the manufacture of individual pipe sections of a pipe formed by a product pipe [( 1 ) and by] having at least one channel [( 5 )] running along the product pipe. The channel is formed by filling a pipe jacket with an insulating mass which exhibits a flowability only in the processing condition. The pipe jacket contains the product pipe and a core which is disposed on the product pipe and which defines the contour of the channel. [( 1 ), in which case the product pipe ( 1 ) and the channel ( 5 ) are fitted with the insulation ( 3 ) enclosed by the jacket pipe ( 2 ). A method consisting of the following process steps is proposed to provide a simple and cost-effective manufacture of almost any type of channel along the product pipe ( 1 ).  
     a) A core ( 7 ) exhibiting at least the outside contour of the channel ( 5 ) is arranged on the jacket surface of the product pipe ( 1 ) in such a manner that the channel ( 5 ) formed by the core ( 7 ) is open along the length of channel ( 5 ) and toward the product pipe ( 1 ) in a linear manner.  
     b) The unit formed by the product pipe ( 1 ) and the core ( 7 ) is inserted in the jacket pipe ( 2 ) and  
     c) The free channel cross-section of the jacket pipe ( 2 ) is filled with an insulating mass that exhibits a flowability only in the processing condition.]

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The invention relates to [concerns] a method for the manufacture of individual pipe sections of a pipe formed by a product pipe and of at least one channel running along the product pipe, particularly a heat channel[,] in which [case] the product pipe and the channel are fitted with an insulation enclosed with a jacket pipe[. Furthermore, the invention concerns] and a pipe manufactured in that manner.

[0005] 2. Description of Related Art

[0006] Practical applications often require [the] pipes to be heated[,] because the products to be transported within the product pipe exhibit [an] appropriate flowability only at a certain temperature. The heating of the pipes is generally achieved with an accompanying heating system consisting of a heat pipe attached to the product pipe used to transport the product. German Patent No. DE-PS 43 14 761, for example, describes a method for the manufacture of individual pipe sections of a pig pipe[,] . The patent describes a method in which the product pipe is fitted with an additional heating pipe[,] through which the heating of the product to be transported in the product pipe is achieved with steam piped at a high pressure as the heating medium.

[0007] Practical applications have shown, however, that the heat transfer between the heating and product pipe is in many cases insufficient due to the linear contact area between the two pipes and due to the fact that steam cannot be used as the heating medium [for safety reasons,] when the product to be transported in the product pipe should [never] not come into contact with water for safety reasons. Furthermore, the known form for the heating channels is disadvantageous for pipes that are not straight, because the fitting of an additional heating pipe to the product pipe is difficult to achieve from a manufacturing point of view, particularly at sharp bends.

OBJECTS OF THE INVENTION

[0008] [The task] It is an object of the invention [consists in the improving of] to provide a method for the manufacture of individual pipe sections of a pipe [in] such [a manner] that [one achieves a] good heat transfer to the product pipe is achieved and [that] any channel [form] shape can be run along the product pipe in a cost-effective manner.

SUMMARY OF THE INVENTION

[0009] [This task is solved with a] A method [of the above-mentioned type] that includes] for the manufacture of individual pipe sections including a product pipe having a jacket surface and at least one channel running along the jacket surface of the product pipe including the following [process] steps:

[0010] a) [A core exhibiting at least the outside contour of the channel is arranged] Arranging a core on the jacket surface of the product pipe [in] such [a manner] that [the channel formed by] the core [is open along the length of channel and toward the] is disposed on the product pipe in a linear manner. The core has both an open surface and a surface facing the product pipe.

[0011] b) [The unit formed by the] Inserting the product pipe [and the] with the core [is inserted in the] into a jacket pipes and

[0012] c) [The free channel cross-section of the] Filling the jacket pipe [is filled] with an insulating mass that exhibits a flowability only [in the] during processing [condition].

[0013] An advantage of the invention is that [Such a method allows the manufacture of] any channel type may be manufactured along the jacket pipe of a product pipe[, i.e.,] with a channel that is open facing the product line.

[0014] Accordingly, it is a feature of the invention to easily [easy to] pull an electric heat conductor through the channel arranged in the [that] manner of the invention. It is also possible to run heating gas through [this] the channel. In addition to utilizing the channel as a heating channel, it is also possible to use it for receiving a detector cable or [as] a so-called “sniffing pipe” to determine leaks in the product pipe.

[0015] These and other objects, advantages, and features of this invention will be apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a cross-section of a preferred embodiment of the invention in a rectangular channel configuration.

[0017]FIG. 2 is a cross-section of a preferred embodiment in a configuration with three U-shaped channels.

[0018]FIG. 3 is a plan view of a preferred embodiment of the invention consisting of two pipe sections.

DETAILED DESCRIPTION OF THE INVENTION

[0019] It was proven particularly advantageous to manufacture the channel by pulling the core out of the jacket pipe after the insulation mass has hardened. In addition to yielding a simple channel manufacture, said method also allows a reuse of the core retrieved in that manner. Pulling the core out of the hardened insulation mass produces a channel that runs along the jacket area of a product pipe and that is open toward the jacket area of the product pipe, thus ensuring a good heat transfer between heating channel and product pipe.

[0020] According to a preferred [design form] embodiment of the invention, the material used for the core consists of an elastic material[,] whose cross-section [changes] decreases with the application of a tensile force. Silicone rubber is such a material, for example. After the insulation mass has hardened, [such] an elastic material is particularly easy to pull out of the pipe section. When applying a tensile force, the outer surface of this elastic core material separates from the hardened insulation mass due to the decreased cross-section and pulling the core out of the channel formed by it requires very little effort [indeed].

[0021] A further [design form in accordance with] embodiment of the invention proposes that the core material consists of a material that is elastic and expands under pressure. For example, such a core can be formed with a hose that maintains its shape by way of a hydraulic or pneumatic pressure until the insulation mass has hardened. The hose will collapse after lowering the pressure and can be pulled out of the jacket pipe.

[0022] A further [design form in accordance with] embodiment of the invention proposes that the core consists of a nonelastic material, to which is applied a separating agent on the outside surface facing the insulation mass and prior to pushing it into the jacket pipe. A core made of a nonelastic material can only be used for generally straight pipe sections, since pulling the core out of the hardened insulation mass would otherwise require much effort. In that respect, the separating agent applied to the outside core surface should reduce the frictional forces between the hardened insulation mass and core. Applying a separating agent has also proven beneficial for a core made of an elastic material.

[0023] According to an alternative [design form of the method in accordance with] embodiment of the invention, the channel that is open toward the product line is produced using a hollow profile that is arranged on the product pipe with its open side facing it and remains in the jacket pipe after the insulation mass has hardened.

[0024] To improve the heat transfer between channel and product pipe and to make the pulling-out of the core from the hardened insulation mass easier, a further [design form] embodiment of the invention proposes that a thin coating that preferably promotes the heat transfer be applied to the core surface facing the insulation mass as well as to the portion of the surface [jacket pipe] of the product pipe touching the core[, i.e.,] preferably prior to pushing it into the jacket pipe.

[0025] According to a preferred [design form] embodiment of the invention, this thin coating that preferably promotes the heat transfer is applied to the core's open surface (the core surface facing the insulation mass) as well as to the whole free jacket surface of the product pipe. In [that] this manner, it is possible to achieve a heat transfer from the channel to the whole jacket surface of the product pipe that is not directly heated. In addition to improving the heat transfer, the use of a thin coating that is applied over the whole jacket surface of the product pipe simplifies a possible recycling of a pipe manufactured in that manner, since the insulation material as well as the product pipe remain almost completely separated. [] Metal foils and particularly aluminum foil represent particularly suitable materials. [] To prevent [this] the thin coating from being pulled out when pulling the core out of the pipe section, a bonding agent can be applied to the thin coating surface facing the insulation material (the outside surface of the thin coating).

[0026] A further [development of this method] embodiment provides for the arranging of a spring-elastic element made of an spring-elastic material such as foam on the core surface facing the insulation mass. When using an electric heat conductor to be introduced in the channel, this elastic element functions as [some type of] a spring element and the heat conductor is [thus] pressed against the jacket surface of the product pipe. [This spring effect is produced as follows: the] The elastic element is [initially] compressed by the filling [with] and hardening of the insulation mass. The elastic element [and] will [again] expand to achieve its original form after the core has been [pulled out] removed. When [additionally] using the thin coating that promotes the heat transfer, the spring-elastic element can be arranged on and/or below [this] the thin coating. When using hollow profiles that remain in the jacket pipe, the spring-elastic element can be arranged on the hollow profile's inside surface facing the channel.

[0027] The method in accordance with the invention can be developed further by fitting the product pipe and core with a spacer prior to inserting them in the jacket pipe, thus ensuring that they occupy a defined position within the jacket pipe.

[0028] Finally, a further [development of the method] embodiment proposes the use of an insulation mass that increases its volume during the hardening process, i.e., [particularly] polyurethane foam. Polyurethane foam presents the advantage that it exhibits a low heat conductivity and a known [certain] compressive strength. [Further details and features of the invention are given in the following description in combination with the respective drawing. The drawings show the following:

[0029]FIG. 1 shows a cross-section of a pipe section fitted with a rectangular channel;

[0030]FIG. 2 shows a cross-section as in FIG. 1, but with three U-shaped channels;

[0031]FIG. 3 shows a combined pipe consisting of two pipe sections.]

[0032] The pipe sections shown in FIGS. 1 and 2 in the form of a cross-section basically consist of inside product pipe 1 [as well as of] and insulation 3 enclosed by jacket pipe 2.

[0033] To maintain product pipe 1 in a predetermined position in jacket pipe 2, product pipe 1 is fitted with spacers 4 exhibiting radially arranged webs to ensure a uniform and preferably coaxial position of product pipe 1 within jacket pipe 2.

[0034] Channel 5 that is open [at least] toward product pipe 1 is provided on the jacket surface of product pipe 1 to receive, for example, an electrical heat conductor [in particular]. In the [design form] embodiment shown in FIG. 1, rectangular channel 5 is arranged on the bottom [side] of product pipe 1, while the [design form] embodiment shown in FIG. 2 shows three U-shaped channels 5 arranged at a spacing on the bottom [side] of product pipe 1.

[0035] To increase the heat transfer between the heat conductor and product pipe 1 and to achieve a separation between product pipe 1 and insulation mass 3 for a possible recycling at a later date, thin layer 6 consisting of a material that preferably promotes the heat transfer is applied [at least] to the jacket surface of product pipe 1 touching channel 5 [as well as to] and the outside surface of channels 5 [or channel 5]. Aluminum foil is a particularly suitable material for thin layer 6. In the [design form] embodiment shown in FIG. 2, thin layer 6 extends across the whole free jacket surface of product pipe 1.

[0036] The first process step in the [The] manufacture of a pipe section exhibiting one or more channels 5 on the jacket surface of product pipe 1 is [achieved as indicated below:

[0037] In a first process step,] to dispose core 7 exhibiting the outside contour of channel 5 [is arranged] on the jacket surface of product pipe 1. To obtain the pipe cross-sections shown in FIGS. 1 and 2, thin layer 6 consisting of an aluminum foil is subsequently placed on the free jacket surface of product pipe 1 as well as on the outside surface of [core 7 or] cores 7.

[0038] Spacers 4 are subsequently arranged [at a spacing] on product pipe 1 and the unit formed by core 7 and product pipe 1 is inserted in jacket pipe 2.

[0039] In addition to using a thin-walled pipe as jacket pipe 2, [a] jacket pipe 2 manufactured by way of a spiral-like coiling and folding of a stretched sheet metal band was proven to be very suitable.

[0040] After inserting the unit formed by core 7 and product pipe 1 in jacket pipe 2, the free cross-section of jacket pipe 2 is closed and the free channel cross-section of jacket pipe is subsequently filled with an insulation mass exhibiting a flowability in the processing condition to form insulation 3. Because polyurethane foam [it] exhibits [only] a low heat conductivity and hardens under pressure, [polyurethane foam] it is considered a particularly suitable insulation mass.

[0041] To form channel 5 that is open toward product pipe 1, core 7 is pulled out of the hardened insulation mass after the insulation mass has hardened. In addition to the simple and cost-effective manufacture of channel 5 that is open toward product pipe 1, this manufacturing method is characterized by the fact that an almost indefinite number of channel runs are possible along the pipe length and a good heat transfer to product pipe 1 is ensured due to the fact that channel 5 is open toward product pipe 1. In addition to being utilized as a heating channel, channel 5 can also be used to receive a detector cable or as a so-called “sniffing pipe” to discover leaks in product pipe 1. In the design form shown in FIG. 2 with three channels 5 arranged on the jacket surface of product pipe 1[,] each channel 5 can possibly be used for a different purpose.

[0042] The connecting of pipe sections produced with this method occurs on site as shown in FIG. 3 in a schematic representation. First, [After] a welded connection [has been] is achieved between product pipes 1 which project[ing] beyond jacket pipe 2, [as well as beyond] insulation 3, and channel 5. Next, a [at the connection point,] channel element 8 is inserted in channels 5 of the piping sections [to be] and connected so as to increase the length of channel 5 beyond the connection point. Product pipe 1 and channel 5 are subsequently insulated in a suitable manner and collar 9 is pushed onto the connection, thus connecting jacket pipes.

[0043] It may not be necessary to insert channel element 8 at the connection point when channels 5 of the pipe sections are used to receive a heat conductor and when an appropriate insulation is ensured at this connection point.

[0044] When channel 5 is used to receive an electric heat conductor, it is advantageous to make the cross-section of the channel several times larger than that of the heat conductor, since this provides the best utilization of the heat convection. Furthermore, this effect is reinforced by rounding the channel corners.

[0045] There are of course other alternate embodiments which are obvious from the foregoing descriptions of the invention, which are intended to be included within the scope of the invention, as defined by the following claims.

[List of Reference Symbols

[0046]1 product pipe

[0047]2 jacket pipe

[0048]3 insulation

[0049]4 spacer

[0050]5 channel

[0051]6 thin layer

[0052]7 core

[0053]8 channel element

[0054]9 collar] 

[patent] We claim[s]:
 1. (Amended) A method for the manufacture of individual pipe sections [of a pipe formed by] comprising a product pipe [(1) and by] having a jacket surface and at least one channel [(5) and particularly a heat channel] running along [the] said jacket surface of said product pipe [(1), in which case the product pipe (1) and the channel (5) are fitted with the insulation (3) enclosed by the jacket pipe (2), characterized by] comprising the following [process] steps: a) [A core (7) exhibiting at least the outside contour of the channel (5) is] arrang[ed]ing a core on said [on the] jacket surface of [the] said product pipe [(1) in] such [a manner] that [the channel (5) formed by the] said core [(7) is open along the length of channel (5) and toward the] is disposed on said product pipe [(1)] in a linear manner[.] such that said core has an open surface and a surface facing said product pipe, b) [The unit formed by the] inserting said product pipe [(1) and the] with said core [(7) is inserted in the] into a jacket pipe; [(2)] and c) [The free channel cross-section of the] filling said jacket pipe [(2) is filled] with an insulating mass that exhibits a flowability only [in the] during processing [condition].
 2. (Amended) [A] The method [in accordance with] of claim 1 [, characterized by] further comprising the [following additional process] step of: [The] pulling said core [(7) is pulled-]out of the jacket pipe [(2)] after [the] said insulation mass has hardened.
 3. (Amended) The [A] method [in accordance with] of claim 2 [, characterized by the fact that the] wherein said core [(7) consists of] is an elastic material[,] whose cross-section decreases when a tensile load is applied.
 4. (Amended) The [A] method [in accordance with] of claim 2 [ characterized by the fact that the] wherein said core [(7) consists of] ifs a material that is elastic and expands under pressure.
 5. (Amended) The [A] method [in accordance with] of claim 3 [, characterized by the fact that the] wherein said elastic material [consists of a] is silicone rubber.
 6. (Amended) The [Al method [in accordance with] of claim 2 [, characterized by the fact that the core (7) consists of a nonelastic material, on which] wherein a separating agent is applied to said open surface of said core [on the outside surface facing the insulation (3) and] prior to [the insertion in the] inserting said product pipe into said jacket pipe [(2)].
 7. (Amended) The [A] method [in accordance with] of claim 1 [, characterized by the fact that the] wherein said core [(7) consists of] has a hollow profile [that remains in the jacket pipe (2)] and is open toward the product pipe [(1)].
 8. (Amended) The [A] method [in accordance with one of] as in any of the preceding claims [1 through 7, characterized by the fact that] further comprising the step of applying a thin coating to the open surface of said core and the portion of the surface of said product pipe which touches said core [layer (6) that preferably promotes the heat transfer is prior to the insertion in the jacket pipe (2) applied to the surface of the core (7) facing the insulation (3) as well as to the jacket surface of the product pipe (1) touching the core (7)].
 9. (Amended) The [A] method [in accordance with one of claims 1 through 7] of claim 8 wherein said thin coating is applied to [characterized by the fact that a thin layer (6) that preferably promotes the heat transfer is prior to the insertion in jacket pipe (2) applied to the surface of the core (7) facing the insulation (3) as well as to] the whole free jacket surface of the product pipe [(1)].
 10. (Amended) The [A] method [in accordance with] of claim [8 or] 9[, characterized by the fact that the thin layer (6)] wherein said thin coating comprises [consists of a foil and particularly of] a metal foil.
 11. (Amended) The [A] method [in accordance with] of claim 8 [, characterized by the fact that the foil material consists of] wherein said thin coating comprises aluminum foil.
 12. (Amended) The [A] method [in accordance with one of claims 8 through 11, characterized by the fact that] of claim 10 wherein said metal foil which is applied to said core has an outside surface which is not in direct contact with said core and a bonding agent is applied to the outside surface [of the thin layer (6)] facing the insulation [(3)] of said metal foil.
 13. (Amended) The [A] method [in accordance with] of claim 2 [, characterized by the fact that] wherein an element comprising [consisting of] a spring-elastic material [such as foam is arranged on the] is disposed on said open surface of [the] said core [(7) facing the insulation (3)].
 14. (Amended) The [A] method [in accordance with claim 13 and] of claim 8 [or 9, characterized by the fact that the] wherein an element comprising a spring-elastic material is disposed on said thin coating [element is arranged on and/or below the thin layer (6)].
 15. (Amended) The [A] method [in accordance with] of claim 7 [, characterized by the fact that the] wherein an element comprising a spring-elastic material is disposed within [element is arranged on the inside of the] said hollow profile [facing the channel (5)].
 16. (Deleted) [A method in accordance with one of claims 1 through 15, characterized by the fact that the channel (5) is in a preferred manner arranged at the bottom side of the product pipe (1).]
 17. (Amended) The [A] method [in accordance with one of claims 1 through 16, characterized by the fact that the] of claim 1 further comprising fitting said product pipe [(1) and the core (7) are prior to their inserting in jacket pipe (2) fitted with the] with spacers [(4), thus ensuring a defined position in the jacket pipe (2)].
 18. (Amended) The [A] method [in accordance with one of claims 1 through 17, characterized by the fact that an] of claim 1 wherein said insulating [insulation] mass [and particularly] is polyurethane foam [is used as the insulation (3) that hardens while increasing its volume].
 19. (Amended) A pipe [with a product pipe exhibiting at least one channel (5) manufactured in accordance with at least one of claims 1 through 18 and arranged on the jacket surface of the product pipe (1), in which case the product pipe (1) is fitted with the insulation (3) enclosed by the jacket pipe (2), characterized by the fact that the channel (5) is open toward the surface of the product pipe (1).] comprising a product pipe having a jacket surface and at least one channel running along said jacket surface of said product pipe made by the following steps: a) arranging a core on said jacket surface of said product pipe such that said core is disposed on said product pipe in a linear manner such that said core has an open surface and a surface facing said product pipe; b) inserting said product pipe with said core into a jacket pipe; and c) filling said jacket pipe with an insulating mass that exhibits a flowability only during processing. 